Pyrrole lower alkanoic acids and derivatives

ABSTRACT

THE INVENTION CONCERNS DIARYL FURAN, THIOPHENE, AND PYRROLE LOWER ALKANOIC ACIDS AND DERIVATIVES WHICH ARE PHARMACOLOGICALLY EFFICACIOUS AS ANTI-INFLAMMATORY AGENTS.

United States Patent 3,644,399 PYRROLE LOWER ALKANOIC ACIDS AND DERIVATIVES Kevan Brown, Reading, and John Frederick Cavalla,

- Iseworth,Middlesex, England, assignors to John Wyeth &. Brothers Limited, Taplow, England .No Drawing. Filed. May 1, 1969, Ser. No. 821,075 Claimsv priority, application Great Britain, May 7, 1968,

Int. Cl. C07d 27/26 US. Cl. 260326.3 7 Claims ABSTRACT OF THE DISCLOSURE The invention concerns diaryl furan, thiophene, and pyrrole lower alkanoic acids and derivatives which are pharmacologically efficacious as anti-inflammatory agents.

(The presentinvention provides compounds of the general formula X R (I) in which X is oxygen, sulphur or NY-, Ar and Ar are aryl radicals (which includes in the description below heteroaryl radicals) and which may be the same or different; R is an aliphatic acid radical containing from two to six carbon atoms or a derivative thereof, Y is a hydrogen atom or an alkyl, cycloalkyl, aralkyl, aryl or heteroaryl radical which may for example be substituted particula'rly :by halogen, nitro, trifluoromethyl or alkoxy groups or an acyl radical, and Z is a hydrogen atom or an alkyl radical. It is to be understood that one of the radicals Ar, Ar and R is in the 2-position and the remaining two of these three radicals are in other positions round .the ring excluding the l-position (i.e. excluding the hetero atom position). Thus, the aryl groups can be in the 2-.and 4- positions, the 2- and 3-positions, the 3- and 4-. positions, the 3- and 5- positions or the 2- and 5- posit'ions, the radical R being substituted on one of the remaining carbon atoms, and Z being substituted on the last remaining carbon atom.

The compounds of the above general formula exhibit pharmacological activity for example anti-inflammatory activity as shown by tests on warm-blooded animals and/ or are intermediates in the preparation of other substituted furans, thiophenes and pyrroles.

Examples of radicals Ar and Ar are unsubstituted phenyl, or phenyl substituted by halogen (for example by fluorine, chlorine or bromine), by lower alkyl (e.g. methyl, ethyl, propyl or butyl), by lower alkoxy (e.g. by methoxy, ethoxy, propoxy or butoxy), by nitro, by amino (including alkyl substituted amino groups) in particular by dialkylamino (e.g. dimethylamino), by tritluorornethyl, by mercapto, by methylthio or by methylsulphonyl, as well as land 2- naphthyl, 2- and 3- furyl, 2- and 3- thienyland 2 3- and 4-pyridyl. The radical R preferably'is' an aliphatic acid radical containing from two .to six carbonatoms more preferably from 2 to fl carbon'a'toins,"'or is'a suitable" derivative thereof, e.g. an

3,644,399 Patented Feb. 22, 1972 ice ester, amide, salt or hydroxamic acid derivative thereof. Preferred examples of radicals R are acetic, n-propionic,

iso-propionic, and butyric acid radicals as well as unsaturated acid radicals, such as acrylic acid. If the acid is in the form of an ester it is preferably the alkyl ester such as ethyl ester. The alkyl or alkoxy groups preferably contain 1 to 4 carbon atoms.

Examples of Z are a hydrogen atom, lower alkyl radicals having up to six carbon atoms, particularly methyl, ethyl, propyl or butyl. Examples of Y are lower alkyl radicals as just mentioned and cycloalkyl radicals such as cyclopentyl and cyclohexyl, aralkyl radicals such as benzyl, phenethyl and 1 or 2- phenyl propyl, aryl radicals such as phenyl or !1- or '2- naphthyl and heteroaryl radicals such as lor 2- thienyl or furyl, 2-, 3- or 4- pyridyl, 2- or 3-indolyl and 1 or 2-pyrrolyl which may be substituted by any of the substituents mentioned above for Ar and Ar or Y can be the acyl residue of a sulphonic oxy-acid such as an aryl sulphonic acid or alkyl sulphonic acid or of an organic carboxylic acid, particularly Y can be an al'kanoyl, cycloal kanoyl, aralkanoyl, aroyl or heteroaroyl residue which can be substituted in the last three cases as aforesaid for Ar and Ar These compounds of general Formula I may be prepared by cyclising a precursor of the furan, thiophene or pyrrole with the simultaneous introduction of the heteroatom. That is to say, the precursor generally is a 1,4- dioxobutane appropriately substituted by the radicals Ar, Ar Z and R Where R is the same as R or is a radical convertible thereto. Such a precursor is a compound having the structure.

fi( JH( JH-(HJ 0 (II) in which the radical Ar is a substituent on one of the carbon atoms, radical Ar on another carbon atom, radical R on a third carbon atom, and a hydrogen atom or alkyl radical is on the fourth carbon atom. The compounds of general 'Formula II can be prepared by reacting an enamine with a l-halo-Z-ketoethane, as is described below for the individual special isomers. R generally is the aliphatic acid, or an alkyl ester thereof, which is desired as radical R.

In order to form a pyroole, a compound of general Formula II can be heated in the presence of ammonia, urea or a primary amine YNH or salt thereof, preferably by heating with ammonium acetate. This is a standard type of reaction for the preparation of pyrroles and may, for example, be carried out at temperatures of 70-l00 C. In this reaction the radical R preferably is an aliphatic acid group. On the other hand, in order to prepare a furan or thiophene from the compound of general Formula II, R preferably is an ester of an aliphatic acid (e.g. the ethyl acetate), in which case the said compound either can be heated with a dehydrating and cyclising agent (preferably an acidic dehydrating agent such as sulphuric acid or a sulphonic acid or phosphorus pentoxide) to give the furan or can be heated with a sulphur-donating dehydrating and cyclising agent (preferably phosphorus pentasulphide or a mixture of hydrogen sulphide and a strong acid such as a hydrohalic acid) to give the thiophene. The ester group in the ensuing com pound can be hydrolysed in standard manner to give the more preferred acid. An inert organic solvent, e.g. benzene or chloroform may be present when preparing the furan or thiophene.

The process for preparing the compounds of the invention is illustrated in more detail below, in which Ar, Ar and R have the meanings defined above, Hal

is a. halogen;ato m and HNAB isanflmine (e.g. morpholine) used to form the enamine.

(1) The reaction of an enarru'ne of Formula III(a) with a haloketone of Formula III(b) yields a 1,3-diaryl-l,4- dicarbonyl compound of Formula III (c) which is cyclised as described above to the 3,5-diaryl-2-R product of Formula III(d).

(2) In a similar manner, the reaction of an enamine of Formula IV (a) With a haloketone of Formula IV (b) yields a l,4-diaryl-l,4-dicarbonyl compound of Formula IV(c) which is cyclised as described above to the 2,5- diary1-3-R product of Formula IV(d).

The 1,4-diaryl-l,4-dicarbony1 compounds of Formula IV(c) wherein Ar and Ar are the same and R represents the diethyl malonate residue (Le.

where R is a hydrogen atom or a lower alkyl residue) can be prepared by Michael addition of the appropriate malonate to a dibenzoyl ethylene of Formula IV(e). This may be cyclised to IV(d) wherein R represents the diethyl malonate residue defined above, or hydrolysed and decarboxylated to give compounds of Formula IV(c) wherein R now represents an acetic or substituted acetic acid residue and then cyclised to compounds of Formula IV(d) wherein R is an acetic or substituted acetic acid residue.

The 1,4-diaryl-l,4-dicarbonyl compounds of Formula IV(c) wherein Ar and Ar are the same or different and R is an alkoxycarbonyl residue can be prepared by alkylating a benzoylacetate of Formula IV(f) with a phenacylbromide of Formula IV(%) in the presence of metallic sodium. W 7 a (3) The reaction of an enamine of Formula V(a) with a haloketone of Formula V(b) yields a l,2-diaryl-l,4-dicarbonyl compound of Formula V(c') which is cyclised as described above to the 2,3-diaryI-5-R product-of Formula V(d). v v 1 (4) The reaction of an enamine of Formula VI(a) with a haloketone of Formula VI(b) yields a 2,3-diaryl-L4 dicarbonyl compound of Formula VI(c) which is cyclised. as described above to the 3,4-diaryl-2-R product of Formula VI(d).

(5) Furthermore, the reaction of an enamine of Formula VII(a) with a halo-carbonyl compound of Formula VII(b) yields a 1,2-diaryl-l,4-dicarbonylcompound of Formula VII(c) which is cyclised as described above to the 2,3-diaryl-4-R product of Formula VII(d) vin ViIid) '1 (6) The reaction of an enamine of Formula VII Ita) with a haloketone of Formula VIII(b) yields a 1,3-diaryl- 1,4-dicarbonyl compound of Formula VIII(c). ,which is c'yclised asdescribed above to the 2,4-diaryl-3-R product of Formula VIII(d) Ar 7 .CH .Hal-OII NA lO Z B Ar VIII(a) VIII(b) Ar R A) (ll Ar ----R n- H 1 21 in v Z Ar" VIII(c) UD Ar Ar 'X (IX) can be prepared following one of the above methods (but with R replaced by hydrogen) and then the radical R can be introduced. Thus, a compound of general Formula (I-) canbe prepared from a compound of general Formula IX using a Reimer-Tiemann reaction, by treating the compound of general Formula (IX) with chloroform in a caustic alkali (e.g. potassium hydroxide) followed by acidification'to give a compound substituted by a formyl group. The formyl group can beconverted to a group of general Formula Kim a known manner, e.g. by reduction to a hydroxymethyl group followed by halogenation and reaction with a cyanide (e.g. potassium cyanide) to give a nitrile which may then be hydrolysed to the amide or acid. Alternatively, the formyl group can be condensed with-amalonic ester and if necessary-subsequent reduction carriedout. Alternatively again, a compound of general EormulaflX) preferably when X is an S or O atom can be; reacted attemperatures below ambient temperature with hydrogen cyanide in an inert solvent which is saturated or nearly saturated with ahydrogen halide; the aldehydeformed can then'be converted to the acid in known manner, A further method" involves oxidising the said aldehyde to the corresponding carboxyl radical by treatment with an alkali metal or alkaline earth metal hydroxide followed by an Arndt-Eistert reaction. Of course, any equivalen't me thod of introducing an aliphatic acidgroup containing two to six carbon atoms into a furan, thiophene. or pyrrole ring can be used.

.As indicated above, if a compound is produced according to theinvention in which the radical R is a nitrile, this may be hydrolysed to theamide or acid. Alternatively,.the. acid may be .esterified to give the ester, or the ester may be reacted ,witlr hydroxylamine to give the hydroxamicacid derivative. Generally the acid is required so. that, i f the ester-is prepared,v this may be hydrolysed.

' If R represents a diethyl malonate residue of formula (wherein R is a hydrogen atom or lower alkyl residue) this may be hydrolysed to the dicarboxylic acid which in turn' can" be decarbox'ylated to the acetic or substituted acetic acid.

Pyrrole compounds in which X is NY- where Y is an alkyl, cycloalkyl, aralkyl, aryl or heteroaryl radical (any of which can be substituted), or an acyl residue, can be prepared from those in which X is -NH- by alkylation or acylation to introduce the desired group Y. If desired any other sensitive group in the molecule can be protected and the protecting group removed after the alkylation or acylation process. It is convenient to prepare N-alkyl, cycloalkyl, aralkyl, aryl or heteroaryl derivatives of the acidic molecules by first protecting the carboxyl group, for instance using an ethyl ester, carrying out the alkylation reaction and finally removing the protecting group. When preparing N-acyl derivatives of the acidic molecules, the carboxyl group is preferably protected by forming the t-butyl ester or benzyl ester these groups being finally removed by heating or catalytic hydrogenation respectively.

As the compounds of general Formula (I) show pharmaceutical activity, for example, anti-inflammatory activity, the invention provides a pharmaceutical composition comprising a compound of general Formula (I), and a pharmaceutically acceptable carrier.

When the compounds of this invention are employed as anti-inflammatory agents they can be administered to Warm-blooded animals, e.g. mice, rats, rabbits, dogs, cats, monkeys, etc. alone or as a pharmaceutical composition in combination with pharmaceutically acceptable carriers. The carrier may be solid, liquid or cream-like and any suitable carrier known to the art can be used. The composition can be in unit dose form, for example as tablets or capsules or it can be in the form of a solution. The compositions can be administered orally or parenterally by injection and the composition can, for parenteral administration, be in the form of a sterile solution or suspension containing other solutes, for example enough saline or glucose to render the solution isotonic. The particular carrier and proportion of carrier to active compound will be determined by the nature of the compound, and the chosen route of administration and standard pharmaceutical practice.

The dosage of the active compound will vary with the form of administration and the particular compound chosen. Furthermore, it will vary with the particular subject under treatment. Generally, treatment is initiated with small dosages substantially less than the optimum dose of the compound. Thereafter, the dosage is increased by small increments until the optimum effect under the circumstances is reached. In general, the compounds of this invention are most desirably administered at a concentration level that will generally afford effective results without causing any harmful or deleterious side effects.

The following examples illustrate the invention:

EXAMPLE 1 2,5-diphenylpyrrole-3-acetic acid (a) 3,4-dibenzoylbutyric acid (200 mg.) is heated with ammonium acetate (1.0 g.) at -100 C. Initially, the mixture gives a clear melt but after 3 minutes, solidifi cation occurs and heating is stopped. On cooling, water is added and the resulting solid is filtered off and recrystallised from aqueous acetic acid to give 2,5-diph'enyl-- zoyl-3-bromopropionic acid (5.0 g.) are heated together in-refiuxi'ng dioxane (50 ml.) for 2' hours. The mixturel is cooled and poured into water, which is then acidified with concentrated hydrochloric acid (0.5 ml.). After'16 hours at room temperature, the mixture is extracted with ether. The ether solution is washed "with2 N 'hydrochloric acid solution, then with water and finally is extracted with 2 N sodium hydroxide solution. The basic solution is washed once with ether and then acidified with concentrated hydrochloric acid solution. The crystalline solid formed is filtered olf and separated by chromatography to give a product M.P. 138 C. and the desired acid M.P. 148-150 C.

In a similar manner the following starting materials give the products indicated:

Starting material Product;

3,4-di-(p-chlorobenzoyl)butyric acid 2,5-di-(p-chlfrophcnyl) pyrrole-3- ac to aci 3,4-di-(p-fluorobenzoyl)butyric acid 2,5-di- (p-fluorophenyl)pyrrole-3- 3,4-di-(m-trifluoromethylbenzoyl) butyric acid. 3,4di(p-methoxybeuzoy1)butync aci 3,4-did(p-methylbenzoly)butyric 3-benzoyl-4-(p-chlorobenzoyl) butyric acid.

4-benzoyl-3-(p-chlorobenzoyl) butyric acid.

4,5-dibenzoylvaleric acid 3,4-di-(p-dimethylaminobenzoyl) butyric acid.

3-benzoyl-i-(p-nitrobenzoyl)- butyric acid.

B-benzoyl-d-(naptho-l-yl)butyric acetic acld. 2,5-di-(m-trifiuoromethylphenyl) pyrrole-3acetic acid. 2,5-di-(p-methoxypheny1) pyrrole- 3-acetic acid. 2,5-di-(p-methy1phenyl) pyrrole- 3-acetic acid. 2-phenyl-5-(p-chlorophenyl) pyrrole-3-acetic acid. 5-phcnyl-2-(p-chlorophenyl) pyrrole-3-acetic acid. 5-(2,5-dipheny1pyrrol-3-y1) propionic acid. 2,5-di-(p-dimethylaminophenyl) pyrrole-Ii-acetic acid. E-(p-nitropheuyl)-2-phenylpyrrole- 3-acetic acid. fi-(naphth-l-yl)-2-pheuylpyrr01c 3-acetic acid. 5-(naphth-2-yl)-2-phenylpyrrole- 3-acetic acid.

aci

3-benzoyl-4-(pyrid-2-ylcarbonyl)- butyric acid.

3-benzoyl-4-(pyrid-3-ylcarbonyl)- butyric aci 3 4-di-(fuIo-2-yl) butyric acid 3 4-di-(theno-2-yDbutyric acid acetic acid. 2-phenyl-5 (thien 3-yl)pyrrole-S- acetic acid. 2-phenyl-5-(pyrid-2-y1)pyrrole3- acetic acid. 2-phenyl-5-(pyrid-3-yl) -pyrrolc-3- acetic aci 2-phenyl-5- (pyrid-4-yl)-pyrrole-3- EXAMPLE 2 2,5-diphenylfuran-3-acetic acid (a) 3,4-dibenzoylbutyric acid is converted into its methyl ester by treatment with diazomethane in ether. Subsequent reaction with phosphorus pentoxide in benzene solution gives the methyl ester of the title acid.

(b) Hydrolysis of the ester of part (a) with sodium hydroxide gives the title acid for M.P. 134-135 C.

In a similar manner the following starting materials give the products indicated:

Starting material 3,4413 (p-chlorobenzoyDbutyric aci 3,4-di-(m-trifluoromethylbeuzoyl) butyric acid. 3,4di(p-methoxybenzoyl)butyric aci 3,4-di(p-methylbenzoyDbutyric aci 3-benzoyli-(p-chlorobenzoyl) butyric aci d-benzoyl-Zi-(p-chlorobenzoyD- butyric acid. 4,5dibenzyivaler1c acid Product 2,5-di(p-chlorophenyl) furan-3- acetic acid. 2,5-di-(p-tluorophenyDiuran-B- acetic acid. 2,5-di-(m-trifluoromethylphenyl)- turan-3-acetic acid. 2,5-di-(p-methoxyphenyl) furan-3- acetic acid. 2,5-di(p-methylpheny1) luran-B- acetic acid. 2-phenyl-fi-(p-chlorophenyl) uran- 3-acetic acid. 5-phenyl-2-(p-chlorophenyl) furan- 3-acetic acid. fl-(2 5diphenylfur-3-yi) propiomc aci EXAMPLE 3 v 2,5-diphenylthiophene-3-acetic acid (a) 3,4-dibenzoylbutyric acid is converted into its methyl ester by treatment with diazomethane in ether. Subsequent reaction of 10.0 g. of this ester with phosphorus pentasulphide (20.0 g.) in benzene solut1on (50 ml.) gives the methyl ester of the title acid.

(b) Hydrolysis of the ester of part (a) with sodium hydroxide-gives the title acid.

In a similar manner the following starting materials give the products indicated.

Starting material Product 3,4-di(p-chlorobenzoyl)butyric 2,5-di-(p-chlorophenyl) thiophence 10 am 2,5-di-(p-fluorophenyl)-thiophcnc- 3-acetic acid. 2,5-di-(m-trifluoromethylphenyD-" thiophene-3 acetic acid. 2,5-di-(p-methoxyphenyl) -th.iophene-B-acetic acid. 2,5-di-(p-methylphenyl)thiophene- 3-acetic acid. 2-phenyl-E-(p-chlorophenyl) thio phene-3-acetic acid. 4-benzoyl3-(pchlorobenzoyl)- 5-pheny1-2-(p-ehlorophenyl)-thiobutyric acid. phene-3-acetie acid. 4,5-dibenzoylvalcn'c acid fl-(2 5-diphenylthieu-3-yl)-proaci 3,4-dii(p-fluorobenzoyDbutyric aci 3,4-di-(m-trifluoromethylbenzoyl) butyric acid.

3,4-d(ii-(p-methoxybenzoyl)butyric aci 3,4-di-(p-mcthylbenzoyDbutyric acid pionic acid.

EXAMPLE 5 Ethyl 3,S-diphenylfuran-Z-acetate [Ethyl 3,6 dioxo 4,6 diphen'ylhe'xanoate;(1.5g) is heated under reflux for 2 hours with phosphorus pentoxide (1.0 g.) in benzene (50 ml.). The organic solution is then decanted and evaporated to give the title furan ester. t T

l EXAMPLE 6 Ethyl 3,5-diphenylthiophene-2-acetate Ethyl 3,6-dioxo-4,6-diphenylhexanoate is heated"with phosphorus pentasulpln'de in benzene to give thetitle thio-' phene ester. 3

EXAMPLE 7 3,4-diphenylpyrrole-2-propionic acid U A (a) The pyrrolidino enamine of phenylacetaldehyde [i.e. 2-(1'-pyrro1idino)styrene] is reacted 'with' ethyl 5- bromo-4-oxo-5-phenyl valerate in asimilar manner tothat described in Example 1(b) to give ethyl 4,7 dioxo-5,6-di-' phenylheptoate. i

(b) The ester of part (a) is hydrolysed to the cor'respending acid and is then treated with ammonium acetate as described in Example 1 (a) to give the title pyrroleacid.

EXAMPLE '8 3,4-diphenylfuran-2-propionic acid (a) Ethyl 4,7-dioxo-5,6-diphenylheptoate (8.0 g.) is. heated under reflux for 3 hours with phosphorus pentoxide (6.0 g.) in benzene ml.). The organic layer is then decanted and evaporated to give the ethyl ester of the title acid. I, I v j (b) The ester of part (a) in ethanol is warmed to 50- C. and treated with a solution of potassium'h'ydroxide (3.0 g.) in water (10 ml.). Evaporation of the solutiomfdisso lution of the residue in water and acidification gives the title furan acid.

EXAMPLE 9 3,4-diphenylthiophenei propionic acid The method of Example 851's repeatedbutusing pliesphorus pentasulphide instead of phosphorus give the title thiophene acid.

pentoxide to .9- EXAMPLE '2,3-diphenylpyrrole-5-propionic acid (a) The reaction of the morpholino enamine of deoxybenzoin and methyl 5-bromo-4-oxo-valerate by the method of Example 1(b) gives methyl:-4;7-dioxo-6,7-diphenylheptoate.

(b) Methyl 4,7-dioxo-6,7-'diphenylheptoate is hydrolysed to the corresponding acid and is then heated with ammonium acetate as described in Example 1(a) to give the title pyrrole acid.

" EXAMPLE .11'

A 2,3-diphenylfuran-5-propionic acid 1(a)"Methyl,4,7-dioxo-6,7-diphenylheptoate is heated at 100 C. with phosphorus pentoxide to give the methyl ester of the title acid.

(b) Hydrolysis of the ester of part (a) with sodium hydroxide gives. the title furanacid.

. v I EXAMPLE 12 2,3-diphenylthiophene-5-propionic acid Il Methyl 4, 7-dioxo6,7-diphenylheptoate is heated at 100 C. with phosphorus pentasulphide to give the methyl ester of thetitle acid.

(b) Hydrolysis of the ester of part (a) with sodium hydroxide gives thetitle thiophene acid.

i EXAMPLE 13 Ethyl 2,3-diphenylpyrrole-4-acetate (a) The morpholino enamine of deoxybenzoin is reacted with ethyl 3 :b'romo-4-oxobutyrate in a manner similar to that described in Example 1(b) to give ethyl 4,5-diphenyl-3iorrnyl-S-oxovalerate.

, .(b) Ethyl 4, 5-diphenyl-3-formyl-5-oxovalerate (4.0 g.) is heated withammonium acetate g.) at 100 C. for 0.25 houriiAddition oi water to, the cooled melt and filtratiofi of the solid gives the title pyrrole ester.

EXAMPLE 14 Ethyl 2,3-diphenylfuran-4-acetate Ethyl "4,5 diphenyl-3-for-myl-5-oxovalerate is heated with phosphorus pentoxide in benzene for 2 hours to give the title furan ester.

V ,7 EXAMPLE 15 12,3Qdiphenylthiophene-4-acetic acid (a)'Ethyl 4-,5-diphenyl 3-formyl-5-oxovalerate is heated withpho'sphor'uspentasulphide to give the ethyl ester of thetitle acid. t

(b) Hydrolysis of the ester of part (a) with sodium hydroxide-givest-he tit-1e thiophene acid.

V EXAMPLE 16 '2,5-diphenylpyrrole-3-acetic acid (a) Diethyl a,B-di-(p-chloroben'zoyl)ethylmalonate is prepared by.-heating under reflux for 19 hours, a mixture of .1 ,Z-di-(p-chlorobenzoyl) ethylene (96.3 g.), diethyl malonate (48.5 ml.), piperidine (6.0 ml.) and absolute ethyl alcohol 300 ml.).lEvaporation under reduced pressure affords a red coloured oily residue which on dissolutionin ether and treating with aqueous hydrochloric acid i smt r (Zl%;)..9 thsj ste l l M-P- 1 1 v 0:. after "recrystallisation froinethylalc'ohol.

Found (percent): C, 59.7; H, 4.6. C H Cl O requires C, 59.4; H, 4.8.

(b) 0a,}8-di-(p-chlorobenzoyl)ethylmalonie acid is prepared by heating under reflux for 2 hours, a mixture of the diester (50 g.) of Example 17(-a) and 2 N aqueous sodium hydroxide solution (100 ml.). Evaporation of the solution gives a residue which is shaken with a mixture of ether and water. Acidification of the aqueous layer gives an oil which after extracting into ether, washing, drying and evaporating gives the di-acid (59.2 g.) as an oil which is used for the next stage without purification.

(c) 3,4-di-(p-chlorobenzoyl)butyric acid is prepared by refluxing for 2 hours, a solution of the di-acid (59.2 g.) of Example 17(b) in dimethylformamide (30 ml.) and then pouring into water (1.5 litre). An oil is precipitated which after extraction into ether, washing with water, drying (MgSO and evaporating gives a brown coloured oil. This oil, which crystallises after a few hours, gives 33.1. g. (67.2%) of the butyric acid which has M.P. 96-97 C.

(d) The acid (10.0 g.) of Example 17(c) and ammonium acetate (20.0 g.) in glacial acetic acid (20 ml.) is heated under reflux for 1 hour. Pouring the solution into water (2 litres) gives a pink coloured solid, recrystallisation of which from benzene affords 7.08 g. (74.5%) of the title pyrrole of M.P. 163-166" C.

Found (percent): C, 62.4; H, 3.7; N, 3.8. CmHmClgNO-v requires C, 62.5; H, 3.8; N, 4.1.

EXAMPLE 18 2,5-di-(p-fluorophenyl) pyrrole-3-acetic acid (a) 1,2-di-(p-fluorobenzoyl)ethylene is prepared by adding dropwise fumaryl chloride (35.2 g., 25 ml.) to a mixture of fluorobenzene (250 ml.) and finely powdered aluminum chloride g.) with stirring and warming to 60 C. The dark red solution is then heated at 70 C. for 0.5 hour followed by pouring into a mixture of ice and concentrated hydrochloric acid (20 ml.). The precipitated solid is extracted into methylene chloride followed by washing with dilute hydrochloric acid, water, drying (MgSO and evaporating which gives an oily residue. Crystallisation from ethyl alcohol aflords 44.2 g. (69.5%) of the substituted ethylene, which has M.P. 163- 164 C. Found (percent): C, 70.7: H, 3.7. C H F O requires C, 70.65; H, 3.7%.

(b) Diethyl a,fi-di-(p-fiuorobenzoyl)ethylmalonate is prepared by the method of Example 17(a) using 1,2-di- (p-fluoroben2oy1)ethylene (42.3 g.), diethyl malonate (24.6 ml.), piperidine (3.0 ml.) and absolute ethyl alcohol (150 ml.). The crude oil (50.0 g.) is used for the next stage without purification.

(c) a,B-di-(p-fluorobenzoyl)ethylmalonic acid is prepared by the method of Example 17(b) using 50.0 g. of crude diester of Example 18(b) and 2 N aqueous sodium hydroxide (100 ml.). The oily product (39.0 g.) is used for the next stage without purification.

(d) 3,4-di-(p-fluorobenzoyl)butyric acid is prepared by the method of Example 17(c) using the di-acid (39.0 g.) of Example 18(c) and dimethylformamide (30 ml.). This oil is again used for the next stage without purification.

(e) The title pyrrole is prepared by the method of Example 17(d) using the butyric acid (16.6 g.) of Exam-' ple 18(d), ammonium acetate (14.0 g.) andglacial acetic acid (30 ml.). The product (2.7 g.).after recrystallisae tion from a mixture of benzene and petroleumether has M.P. 143-144" C.

Found (percent): C, 68.6; H, 3.9; N,4.3. C H F NO requires C, 69.0; H, 4.2; N, 4.5.

EXAMPLE 19 2,5 -dip-methoxyphenyl pyrrole-3-acetic acid tat'e (4.5 g.) is heated'under reflux for 1 hour and' -theri' worked up as described in Example 17(d) to give the title compound.

Found (percent): C, 71.3; H, 5.65; N, 4.05. C H NO requires C, 71.3; H, 5.7; N, 4.2.

EXAMPLE 20 2,5 -di- (p-tolyl) pyrrole-3-acetic acid A mixture of 3,4-di-(p-methylbenzoyl)butyric acid (33.3 g.), glacial acetic acid (60 ml.) and ammonium acetate (34.05 g.) is heated under reflux for 1 hour and then worked up as described in Example 17(d) to give the title acid.

EXAMPLE 21 2,5-diphenylfuran-3-acetic acid (a) A mixture of 10.0 g. of diethyl B-dibenzoylethylmalonate [prepared by the method of Example 17(-a)], phosphoric oxide (50.0 g.) and dry benzene (250 ml.) is heated under reflux for 1 hour. The solvent is then decanted from the solid material after which the solid is treated with water and benzene. Separating the benzene layer, washing with water, drying (MgSO and evaporating affords the furan-diester (5.35 g.) as an oil which is used for the next stage.

(b) The above furan-diester (5.35 g.) and 2 N aqueous sodium hydroxide solution (50 ml.) is heated on a steambath for 0.5 hour and the ethanol produced 'is evaporated. The aqueous solution is washed with ether and after treating with charcoal it is acidified with concentrated hydrochloric acid. Filtering off the solid, drying and recrystallising from benzene gives 2.75 g. of the furan diacid of M.P. 143-144 C.

Found (percent): C, 70.1; H, 4.3. C H O requires C, 70.8; H, 4.4.

(0) Heating under reflux for 1 hour a solution of the above di-acid (2.55 g.) in dimethylformamide ml.) and then pouring into water (500 ml.) gives a precipitate which is extracted into ether and after washing several times with water is extracted with saturated aqueous sodium hydrogen carbonate solution. The basic extract is decolourised with charcoal and after filtering is acidified to give a colourless precipitate which is filtered off and dried. Recrystallisation from a mixture of benzene and petroleum ether (B.P. -60 C.) affords 0.77 g. of the title furan acetic acid of M.P. 134-135 C.

Found (percent): C, 77.2; H, 5.0. C H O requires C, 77.4; H, 5.1.

EXAMPLE 22 2,5-di- (p-chlorophenyl)furan-3-acetic acid This compound is prepared by the procedure of Example 21, starting from 30.0 g. of the diester of Example 17(a). Recrystallisation of the crude acid from benzene affords 16.3 g. of the title compound of M.P. 153154 C.

Found (percent): C, 62.6; H, 3.6. C H Cl O requires C, 62.3; H, 3.5.

EXAMPLE 23 2,5 -di- (p-fluorophenyl) furan-3-acetic acid A solution of 6.8 g. of the crude acid of Example 18(d) in glacial acetic acid (30 ml.) containing a few drops of concentrated sulphuric acid is heated under reflux for 1 hour and then cooled. Addition of water gives a solid which is filtered oflF, washed with water and dried. 'Recrystallisation from benzene afiords 4.48 g. of the title acid of M.P. 160-161 C.

Found (percent): C, 69.0; H, 3.85. C H F O requires C, 68.85; H, 3.85.

EXAMPLE 2'4 2,5-di- (p-methoxyphenyl) furan-3-acetic acid A mixture of 3,4-di-('p-methoxybenzoyl)butyric acid (4.0 g.), glacial acetic acid (10 ml.) and concentrated sulphuric acid (1 drop) is heated under reflux for 1 hour and then worked up as described in Example 23. Recrystallisation from benzene gives the title acid. Found (percent): C, 77.4; H, 5.5. C d-1 0 requires C, 71.1; H, 5.4. I EXAMPLE 25 2,5-di-(p-tolyl)furan-3-acetic acid 2- (p-chlorophenyl) -5-phenylfuran- 3-aceti-c acid I (a) Sodium (2.3 g.) is added to a stirred solution of ethyl p-chlorobenzoylacetate*(22.7 g.) in ether (300 ml.), in an atmosphere of nitrogen.;After heating under reflux for 6 hours the mixture-is cooled and treated with phenacylbromide (20.0 g.) followed 'by further heating under reflux for 1.5 hours. The mixture is again cooled and treated with water. Separating the organiclayer, drying (MgSO and evaporating gives 40.0 g. of ethyl 2 (p-chlorobenzoyl 3 benzoylp'ropionate as a red oil.

(b) Refl-uxing a mixture of 5.0 got the ester of part (a) and glacial acetic acid (40 ml.) and concentrated sulphuric acid (2 drops) for 1 hour and working-up as. described in Example 23 gives 2 (p-chlorophenyD-Iiethoxycarbonyl-S-phenylfiuran. I i

(c) The ethoxycarbonyl compound of part (b) is reduced in ether with aluminium lithium hydride to give the corresponding hydroxymethyl compound. Subsequent chlorination, treatment with an alkali metal cyanide and hydrolysis affords the title compound.

EXAMPLE 27 v v 5- (p-chlorophenyl)-2-phenylfuran-3 acetic acid (a) The method of Example 27 (a)using ethyl ben zoylacetate and p-chlorophenacylbrornide gives ethyl 3-' (p-chlorobenzoyl)-2-benzoylpropionate.

b) Refluxing a mixture of 2.0 g. of the ester of part (a) and glacial acetic acid (20 ml.) and concentrated sulphuric acid (2 drops) for 1 hour and working up as described in Example 23 gives 1.5 g. of 5 -"(-p-chlorophenyl)-3-ethoxycarbony1 2 phenyl-furan-of '73- 74 C. after recrystallising from ethanol.

Found (percent): C, 69.9;1-1, 4.6L Ci H' ClO requires C, 69.8; H, 4.6. p

(c) The ethoxycarbonyl compound of part (b) is reduced in ether with aluminium lithiu'rn'hydride to give the corresponding hydroxymethyl compound. Subsequent chlorination, treatment with an alkali metal cyanideand hydrolysis affords the title compound.. I

EXAMPLE 2's 2,5-diphenylthiophene-3-acetic acid 13 EXAMPLE 29 Ethyl 3,5-diphenylpyrrole-2-acetate (a) The morpholino enamine of acetophenone [i.e. 1- (4'-morpholino)styrene] is treated With ethyl 4-bromo-4- phenylacetoacetate in a manner similar to that described in Example 1 (b) to give ethyl 3,6-dioxo 4,6 diphenylhexanoate.

(b) Heating ethyl 3,6 dioxo 4,6 diphenylhexanoate with ammonium acetate in glacial acetic acid according to the method of Example 17(d) gives the title pyrrole ester.

EXAMPLE 30 3,S-diphenylpyrrole-Z-acetic acid The pyrrole ester (5.0 g.) of Example 29(b) in ethanol (50 ml.) is treated with a solution of potassium hydroxide (3.0 g.) in Water ml.) and is then warmed to 50 C. for 0.5 hour. The excess of alcohol is removed under reduced pressure and the residue is dissolved in water (50 ml.). Acidification with hydrochloric acid precipitates the title acid which is filtered 011 and dried.

EXAMPLE 31 Ethyl 3,5-diphenylfuran-2-acetate Heating ethyl 3,6 dioxo 4,6 diphenylhexanoate [prepared by method of Example 29(a)] with glacial acetic acid and concentrated sulphuric acid according to the method of Example 23 gives the title furan ester.

EXAMPLE 32 3,S-diphenylfuran-Z-acetic acid The furan ester of Example 31 is hydrolysed with potas sium hydroxide as described in Example to give the title acid.

- EXAMPLE 33 Ethyl 3,5-diphenylthiophene-2-acetate Cyclising ethyl 3,6 dioxo 4,6 diphenylhexanoate [prepared by method of Example 29 (a)] in chloroform solution with hydrogen chloride and hydrogen sulphide according to the method of Example 28 gives the title thiophene ester.

. EXAMPLE 34 3,5-diphenylthiophene-Z-acetic acid Hydrolysis of the ester of Example 33 with potassium hydroxide by the method of Example 30 gives the title EXAMPLE 36 Ethyl 3,4-diphenylfuran-Z-propionate Heating ethyl 4,7 dioxo 5,6 diphenylheptoate [prepared by method of Example (a)] With glacial acetic acid and concentrated sulphuric acid by the method of Example 23 gives the title furan ester.

EXAMPLE 37 3,4-diphenylfuran-2-propionic acid The furan ester of Example 36 is hydrolysed with potassium hydroxide as described in Example 30 to give the -title a ci d.

14 EXAMPLE 3:;

Ethyl 3,4-diphenylthiophene-Z-propionate Cyclising ethyl 4,7-dioxo-5,6-diphenylheptoate [prepared by method of Example 35(a)] in chloroform solution With hydrogen chloride and hydrogen sulphide according to the method of Example 28 gives the title thiophene ester. EXAMPLE 39 3,4-diphenylthiophene-2-propionic acid Hydrolysis of the ester of Example 38 with potassium hydroxide by the method of Example 30 gives the title thiophene acid.

EXAMPLE 40 2,4-diphenylpyrrole-3-acetic acid (a) The pyrrolidino enamine of phenylacetaldehyde [i.e. 2-(l'-pyrrolidino)-styrene] is reacted with B-benzoyl- B-bromopropionic acid in a similar manner to that described in Example 1(b) to give 3-benzoyl-5-oxo-4-phcny1- valeric acid.

(b) Heating 3-benzoyl-S-oxo-4-phenylvaleric acid in glacial acetic acid With ammonium acetate by the method described in Example 17(d) gives the title pyrrole acid.

EXAMPLE 41 2,4-diphenylfuran-3-acetic acid Heating 3-benzoyl-5-oxo-4-phenylvaleric acid with glacial acetic acid and concentrated sulphuric acid by the method of Example 23 gives the title furan acid.

[EXAMPLE 42 Ethyl 2,4-diphenylthiophene-3-acetate (a) Ethyl 3-benzoyl-5-oxo-4-phenylvalerate is prepared by the method of Example 1(b) using ethyl fi-benzoyl-flbromopropionate and the pyrrolidino enamine of phenylacetaldehyde [i.e. 2-(1'-pyrrolidino)styrene].

(b) Cyclisation of ethyl 3-benzoyl-5-oxo-4-phenylvalerate in chloroform solution with hydrogen chloride and hydrogen sulphide according to the method of Example 28 gives the title thiophene ester.

EXAMPLE 43 2,4-diphenylthiophene-3-acetic acid Hydrolysis of the ester of Example 42 with potassium hydroxide by the method of Example 30 gives the title thiophene acid.

EXAMPLE 44 2,3-diphenylpyrrole-4-acetic acid Hydrolysis of the ester of Example 13(b) With potassiumhydroxide by the method described in Example 30 gives the title pyrrole acid.

EXAMPLE 45 Ethyl 2,3-diphenylfuran-4-acetate Heating ethyl 4,5-diphenyl-3-formyl 5 oxo valerate [prepared by the method of Example 13(a)] with concentrated sulphuric acid in glacial acetic acid by themethod of Example 23 gives the title furan ester.

EXAMPLE 46 2,3-diphenylfuran-4-acetic acid Hydrolysis of the ester of Example'45 with potassium hydroxide by the method of Example 30 gives the title furan acid.

EXAMPLE 47 Ethyl 2,3-diphenylthiophene-4-acetate Cyclising ethyl 4,5-diphenyl 3 formyl-S-oxovalerate [prepared by the method of Example 13(a)] .in chloro-.

form solution with a mixture of hydrogen chloride and hydrogen sulphide according to the method of Example 28 gives the title thiophene ester EXAMPLE 48 2,3-diphenylthiophene-4-acetic acid Hydrolysis of the ester of Example 47 with potassium hydroxide according to the method of Example 30 gives the title thiophene acid.

EXAMPLE 49 2,3-diphenylpyrrole-S-propionic acid Methyl 2,3-diphenylfuran--propi0nate Methyl 4,7-dioxo-6,7-diphenylheptoate is cyclised in a mixture of glacial acetic acid and concentrated sulphuric acid by the method of Example 23 to give the title furan ester.

EXAMPLE 51 2,3-diphenylfuran-5-propionic acid Hydrolysis of the ester of Example 50 using potassium hydroxide by the procedure of Example 30 gives the title furan acid.

EXAMPLE 52 Methyl 2,3-diphenylthiophene-5-propionate Cyclising methyl 4,7 dioxo-6,7-diphenylheptoate in chloroform solution with a mixture of hydrogen chloride and hydrogen sulphide according to the method of Exampic 28 gives the title thiophe-ne ester.

EXAMPLE 53 2,3-diphenylthiophene-S-propionic acid Hydrolysis of the ester of Example 52 using potassium hydroxide by the procedure described in Example 30 gives the title thiophene acid.

EXAMPLE 54 S-(p-aminophenyl)-2-phenylpyrrole-3-acetic acid The corresponding p-nitro compound of Example 1 is reduced with hydrogen in the presence of palladium on charcoal catalyst to give the title pyrrole acid.

EXAMPLE 55 a [2,5 -dip-chlorophcnyl) pyrro1-3 -yl] u-methylacetic acid The title compound is prepared in a similar manner to that described in Example 17 except that diethyl methylmalonate is used for the Michael reaction instead of diethyl malonate.

EXAMPLE 56 2,5-di- (p-chlorophenyl)furan-3-acetamide The furan acetic acid of Example 22 is converted into the acid chloride by treatment with thionyl chloride. Subsequent treatment with ammonia gives the title amide.

EXAMPLE 57 2,5-di- (p-chlorophenyl)furan-3-acethydroxamic acid The furan acetic acid of Example 22 is esterified with hydrogen chloride in ethyl alcohol and the ester subsequently treated with hydroxylamine to give the title hydroxamic acid.

1 6 EXAMPLE 5 s 2,5-diphenyl-4-methylpyrrole-3-acetic acid (a) 1,Z-dibenzoyl-1,-methylethylene is prepared by adding dropwise mesaconyl dichloride to a mixture of benzene and finely powdered aluminium chloride with stirring and warming to 60 C. The solution is then heated at C. for 0.5 hour followed by pouring into a mixture of ice and concentrated hydrochloric acid. The mixture is extracted with methylene chloride and the extract is washed with dilute hydrochloric acid and water. Drying over magnesium sulphate and evaporating gives the substituted ethylene.

(b) Diethyl a,,B-dibenzoylpropylmalonate is prepared by the method of Example 17(a) using 1,2-dibenzoyl-lmethylethylene, diethyl malonate, piperidine and ethyl alcohol.

(c) 0:,5-dibenzoylpropylmalonic acid is prepared by the method of Example 17(b) using the diester of part (b) and aqueous sodium hydroxide.

(d) 3,4-dibenzoylvaleric acid is prepared by the method of Example 17(c) using the di-acid of part (c) and dimethylformamide.

(e) The title pyrrole acid is prepared by the method of Example 17(d) using the valeric acid of part ((1), ammonium acetate and glacial acetic acid.

EXAMPLE 59,

2,5-di-(p-chlorophenyl)-N-phenylpyrrole-3-acetic acid A mixture of 5.56 g. of the diketo-acid of Example 17(c), aniline (1.86 g.) and p-toluenesulphonic acid (50 mg.) in toluene (50 ml.) is heated under reflux for 1 hour using a Dean and Stark water separator. The mixture is then cooled and the solid filtered oif and dried to give 4.0 g. of the title pyrrole acid.

Found (percent): C, 68.1; H, 4.1; N, 3.4. C24H17C12NO2 requires C, 68.2; H, 4.3; N, 3.3.

In a similar manner the following amines give the products indicated:

Amine Product p-Chloroauiline 1,2,fiigri-(p-chlorophenyl)pyrrolc-3-acetic f m-Trifiuoromethylaniline. 2,5-di-(pchlorophenyl)-N-(m-trifluoromethylphenyl)pyrrolei racetic acid.

pMethoxyaniline 2,5-di-(p-chlor0pheuyl)-N-(p-methoxyphenyl)pyrrole3-acetic acid.

p-Toluidine 2,5-di-(p-ch1orophenyl)-N-(p-to1yl) v 4 pyrrole-3-acetic acid. I p-Nltroamhne 2,5-di-(p-chlorophenyl)-N (p-nitropheny1) pyrrole-3ncetic acid. p-Dimethylaminoani1inc 2,5-di-(p-chloropheny1)-N-(p-diniethylaminophenyl)pyrrole-S-acetic acid.

4-aminopy1'idine. 2,5-di-(p-chlorophenyl) -N-(pyrid-4-yl) pyrrole-3-acetic acid. Benzylamine N-benzyl-Z,5-di-(pphloropheuyl)pyrrole- 3-aeetic acid. cyclohexylamme N-cyclohexyl-2,5-di-(p-chlorophenyl)- pyrrole-3-acetic acid.

EXAMPLE 60 requires C, 63.35; H, 4.2; N, 3.9).

EXAMPLE 61 N- (p-chlorobenzoyl) -2,5-di p-fiuorophenyl) pyrrole-3-acetic acid (a) A solution of 2,5 di-(p-fluorophenyl)pyrrole 3- acetic acid in tetrahydrofuran is treated with cyclohexyl- Acid halide Product Acetyl chloride N-acetyl-2,5-di-(p-fluorophenyl) 'pyr'role-Zi-acetic acid. Cyclohexylcarbonyl chloride N-cyclohexylc'arbonyl-2,5-di- (p tdluoropheuyl)pyrrole-3-acetic ac1 Phenylacetyl chloride N-phenylacety1-2,5-di-(pfiucgophenyl)pyrrole-3-acetlc -aci Benzoyl chloride N-benzoyl-2,5-di-(p-fluorophenyl) pyrrole-E-acetic acid. p-Methylbenzoyl chloride; N-(p methylbenzoyD-Zj-di- (p-fiuorophenyl)pyrrole-3- acetic acid. p-Methoxybenzoyl chloride N-(p-methoxybenzoyl)-2,5-di- (p-fiuorophenyl)pyrrole-3- acetic acid. p-Nitrobenzoyl chloride N-(p-nitrobenzoy1)-2,5-d1(pacld. p-Dimethylaminobenzoyl chloride. N-(p-dimethylaminobenzoyl)- 3-acetic acid. m-Trifluoromethylbenzoyl chloride. N-(m-trifluoromethylbenzoyl)- 3-acetic acid. l-naphthoyl chloride N-(1-naphthoyl)-2,5d1-(p 2-furoyl chloride N-(2-furoyl)-2,fi-di-(p-fiuoro;

phenyl)pyrrole-3-acet1c acid.

2-thanoyl chloride N-(2-thenoyl)-2,5-di-(p-fluorophenyDpynole-B-acetic acid.

4-pyridylcarbonyl chloride N-(4-pyridylcarbonyl)-2,5-di- (pguorophenyl)pyrrolc3-acet1c 2-pyrrylcarbony1 chloride N-(2-pyrrylcarbonyl)-2,5-di- (p-fluoropheny1)pyrrole-3- acetic acid.

EXAMPLE 62 N-(p-aminobenzoyl) -2,5-di-(p-fiuorophenyl) pyrrole-3-acetic acid The p-nitro compound of Example 61 is reduced with hydrogen in the presence of palladium on charcoal catalyst to give the title pyrrole acid.

In the pharmacological evaluation of the properties of the compounds of this invention, the effects in vivo of the compounds are tested in the procedure of Winter et al. in Proc. Soc. Biol. Med., 111, 544 (1962) and Buttle et al. in Nature, 179, 629 (1957).

The compounds of general Formula I when administered orally in the above test procedure at a dosage of to 250 mg./ kg. depending on the compound in question, demonstrated anti-inflammatory activity.

Good activity was obtained with 2,5 di-(p-fiuorophenyl)pyrrole 3 acetic acid, 2,5 di-(p-methoxypheny1)furan 3 acetic acid, 2,5 diphenylpyrrole-3- acetic acid, 2,5-diphenylfuran-3-acetic acid, 2,5 di-(p chlorophenyl)pyrrole-S-acetic acid and 2,5 di-(p-chlorophenyl)furan 3 acetic acid as shown in the following table which shows the percent inhibition of the rat paw oedema and dosage tested.

18 EXAMPLE 63 Mg. 2,5-di-(p-fluorophenyl)pyrrole-3-acetic acid .125 Lactose Magnesium stearate 5 Capsules of the above were made up by thoroughly mixing together batches of the above ingredients and filling hard gelatine capsules (250 mg.) with the mixture.

EXAMPLE 64 Mg. 2,5-diphenylpyrrole-3-acetic acid Lactose 100 Avicel 30 Dried maize starch 40 Magnesium stearate 5 Tablets of the above composition were made by milling the active ingredient to 40 mesh (British Standard), sieving through a 40 mesh (British Standard) sieve, mixing the milled material with the other components and compressing to form tablets.

What is claimed is:

1. A compound having the formula:

in which Ar and Ar are each radicals of the group consisting of phenyl, halophenyl, loweralkylphenyl, loweralkoxyphenyl, nitrophenyl, aminophenyl, diloweralkylaminophenyl, trifluoromethylphenyl, 1- and 2- naphthyl, 2- and 3- furyl, 2- and 3- thienyl and 2-, 3- and 4- pyridyl; R is a member of the group consisting of radicals having the formula 0 CH 0 II I II C in which X is a member of the group consisting of O-H, NH NHOH, and lower alko'xy; Y is a member of the group consisting of hydrogen, lower alkyl, cy-clolowe'ralkyl, phenyl lower alkyl, phenyl, halophenyl, loweralkylphenyl, loweralkoxyphenyl, nitrophenyl, diloweralkylaminophenyl, and trifluoromethylphenyl, and Z is a member of the group consisting of hydrogen and lower alkyl.

2. A compound having the formula 20 loweralkoxyphenyl and trifluoromethylphenyl; and R is a member of the group consisting of and their lower alkyl esters.

3. A compound according to claim 2 which is 2,5-diphenylpyrrole-3-acetic acid.

4. A compound according to claim 2 which is 2,5-di- (p-fluorophenyl)pyrrole-3-acetic acid.

5. A compound according to claim 2 which is 2,5-di- (p-methoxyphenyl)pyrrole-S-acetic acid. 7

6. A compound according to claim 2 which is 2,5-di- (p-toly1)pyrrole-3-acetic acid.

7. A compound according to claim 2 which is 2,5-di- (p-chlorophenyl)pyrrolc-3-acetic acid. H V

References Cited UNITED STATES PATENTS 3,487,089 12/1969 Umio Ct al 260-3 13.1

ALEX MAZEL, Primary Examiner J. A. NARCAVAGE, Assistant Examiner US. Cl. X.R.

260-295 R, 295.5 R, 332.2 A, 347.3, 347.4, 469; 424- 

